.container {
  width: 600px;
  height: 300px;
  overflow: hidden;
  background: yellow;
  position: relative;
}

.inner {
  animation-duration: 5s;
  animation-timing-function: linear;
  animation-iteration-count: 1;

  -webkit-animation-duration: 5s;
  -webkit-animation-timing-function: linear;
  -webkit-animation-iteration-count: 1;

  display: flex;
  background: #f0f0f0;
  position: absolute;
}

.inner1 {
  animation-name: gallary1;
  left: 0;
}

.inner2 {
  animation-name: gallary2;
  animation-delay: 5;
  top: 140px;
  /* left: -800px; */
}

.item {
  width: 100px;
  height: 100px;
  margin: 10px;
}

@keyframes gallary1 {
  from {
    left: -200px;
  }
  to {
    left: 300px;
  }
}

@-webkit-keyframes gallary1 /* Safari and Chrome */ {
  from {
    left: -200px;
  }
  to {
    left: 300px;
  }
}

@keyframes gallary2 {
  from {
    left: -800px;
  }
  to {
    left: 300px;
  }
}

@-webkit-keyframes gallary2 /* Safari and Chrome */ {
  from {
    left: -200px;
  }
  to {
    left: 300px;
  }
}
